One of the UK's biggest energy firms is to close its last coal-fired power station, threatening the loss of almost 160 jobs.

Scottish and Southern Energy said the Fiddler's Ferry site at Warrington in Cheshire, will shut by the end of March 2020, saying it faced "unsustainable" losses.

Union officials described the news as a "real blow" to the workforce, but the company said it will seek to avoid compulsory redundancies where possible.

Stephen Wheeler, of SSE, said: "The proposed closure of SSE's coal-fired power station at Fiddler's Ferry is a very difficult decision because of the impact on our employees and contractors at the station, their families and the local community.

"Fiddler's Ferry is SSE's last operational coal-fired station. Environmentally, coal is a major emitter of CO2, and the UK Government has committed to ending unabated coal-fired electricity generation by 2025 at the latest.

"Financially, Fiddler's Ferry is loss-making and our projections show that it will continue to be so. These losses are unsustainable beyond the end of the current financial year.

"As we move towards the proposed closure, our priorities are to keep the site operating safely and effectively and to ensure that employees have a range of options available to them for the future.

"SSE is keen to ensure, where possible, that employees are redeployed across other parts of the SSE group. SSE will also offer employees voluntary redundancy on enhanced terms and will seek to avoid compulsory redundancies."

Sue Ferns, of the Prospect union, said: "Today's announcement is a real blow to the dedicated staff at Fiddler's Ferry after a long period of uncertainty about the future.

"Prospect understands the necessity of transitioning away from high carbon generation, however we believe that it is essential that workers are supported during this transition, and we will be working on behalf of those affected through this difficult period.

"The failure to resolve the hiatus in the capacity market and the wider uncertainty around energy policy have undoubtedly contributed to this decision, it is absolutely essential that the Government brings forward the Energy White Paper as soon as possible to give the industry a clear framework for the future."

Unite union regional officer Graham Williams said: "This is very grim news for the workforce - ranging from admin to engineering jobs - and their families, as well as being a devastating blow for the economy in the North West.

"While we recognise that coal-fired electricity generation is being phased out, Fiddler's Ferry plays a significant role in providing back-up when there are surges in energy demand during cold snaps and the National Grid is seeking additional supplies.

"The fact that the Government is not prepared to pay an economic price to have this reserve at the ready shows that ministers are more interested in the internal energy market than the country's national interest."